package com.zzvcom.utils;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

/**
 * 反射的Utils函数集合. 提供访问私有变量,获取范型类型Class,提取集合中元素的属性等Utils函数.
 * 
 * @author 赖君玉
 */
public class ReflectionUtils
{

    private static Logger logger = LoggerFactory
            .getLogger(ReflectionUtils.class);


    /**
     * 直接读取对象属性值,无视private/protected修饰符,不经过getter函数.
     */
    public static Object getFieldValue(final Object object,
            final String fieldName)
    {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException("Could not find field ["
                    + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        Object result = null;
        try
        {
            result = field.get(object);
        }
        catch (IllegalAccessException e)
        {
            logger.error("不可能抛出的异常{}", e.getMessage());
        }
        return result;
    }

    /**
     * 直接设置对象属性值,无视private/protected修饰符,不经过setter函数.
     */
    public static void setFieldValue(final Object object,
            final String fieldName, final Object value)
    {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException("Could not find field ["
                    + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        try
        {
            field.set(object, value);
        }
        catch (IllegalAccessException e)
        {
            logger.error("不可能抛出的异常:{}", e.getMessage());
        }
    }

    /**
     * 循环向上转型,获取对象的DeclaredField.
     */
    protected static Field getDeclaredField(final Object object,
            final String fieldName)
    {
        Assert.notNull(object);
        return getDeclaredField(object.getClass(), fieldName);
    }

    /**
     * 循环向上转型,获取类的DeclaredField.
     */
    @SuppressWarnings("unchecked")
    protected static Field getDeclaredField(final Class clazz,
            final String fieldName)
    {
        Assert.notNull(clazz);
        Assert.hasText(fieldName);
        for (Class superClass = clazz; superClass != Object.class; superClass = superClass
                .getSuperclass())
        {
            try
            {
                return superClass.getDeclaredField(fieldName);
            }
            catch (NoSuchFieldException e)
            {
                // Field不在当前类定义,继续向上转型
            }
        }
        return null;
    }

    /**
     * 强制转换fileld可访问.
     */
    protected static void makeAccessible(Field field)
    {
        if (!Modifier.isPublic(field.getModifiers())
                || !Modifier.isPublic(field.getDeclaringClass().getModifiers()))
        {
            field.setAccessible(true);
        }
    }

    /**
     * 通过反射,获得定义Class时声明的父类的范型参数的类型. 如public UserDao extends HibernateDao<User>
     * 
     * @param clazz The class to introspect
     * @return the first generic declaration, or Object.class if cannot be
     *         determined
     */
    @SuppressWarnings("unchecked")
    public static Class getSuperClassGenricType(Class clazz)
    {
        return getSuperClassGenricType(clazz, 0);
    }

    /**
     * 通过反射,获得定义Class时声明的父类的范型参数的类型. 如public UserDao extends HibernateDao<User,Long>
     * 
     * @param clazz clazz The class to introspect
     * @param index the Index of the generic ddeclaration,start from 0.
     * @return the index generic declaration, or Object.class if cannot be
     *         determined
     */

    @SuppressWarnings("unchecked")
    public static Class getSuperClassGenricType(Class clazz, int index)
    {

        Type genType = clazz.getGenericSuperclass();
        
        if(clazz.getSimpleName().indexOf("$$EnhancerByCGLIB$$")>0)
        {
            return Object.class;//如果是代理对象就不用找了
        }
        
        if (!(genType instanceof ParameterizedType))
        {
            logger.warn(clazz.getSimpleName()
                    + "'s superclass not ParameterizedType");
            return Object.class;
        }

        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

        if (index >= params.length || index < 0)
        {
            logger.warn("Index: " + index + ", Size of "
                    + clazz.getSimpleName() + "'s Parameterized Type: "
                    + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class))
        {
            logger
                    .warn(clazz.getSimpleName()
                            + " not set the actual class on superclass generic parameter");
            return Object.class;
        }        
        return (Class) params[index];
    }

    /**
     * 提取集合中的对象的属性,组合成List.
     * 
     * @param collection 来源集合.
     * @param propertityName 要提取的属性名.
     */
    @SuppressWarnings("unchecked")
    public static List fetchElementPropertyToList(final Collection collection,
            final String propertyName) throws Exception
    {

        List list = new ArrayList();

        for (Object obj : collection)
        {
            list.add(PropertyUtils.getProperty(obj, propertyName));
        }

        return list;
    }

    /**
     * 提取集合中的对象的属性,组合成由分割符分隔的字符串.
     * 
     * @param collection 来源集合.
     * @param propertityName 要提取的属性名.
     * @param separator 分隔符.
     */
    @SuppressWarnings("unchecked")
    public static String fetchElementPropertyToString(
            final Collection collection, final String propertyName,
            final String separator) throws Exception
    {
        List list = fetchElementPropertyToList(collection, propertyName);
        return StringUtils.join(list, separator);
    }
}
